Why the US and much of Europe are shivering in the cold

Image courtesy NOAA/NWS Climate Prediction Center.

Bob Henson | 8 January 2010 • No matter how you slice it, the last few weeks have been consistently wintry across large chunks of North America and Eurasia. To cite just one example: in NCAR’s hometown of Boulder, Colorado, the warmest temperature recorded during December was a mere 57°F (13.9°C). Only one other month in the last 20 years saw such a modest maximum, according to UCAR’s Matthew Kelsch. We’ll take a closer look next week at this winter’s cold intrusions—including the one now slicing across the U.S. Southeast—and examine just how unusual they really are.

In the meantime, winter weather galore is unfolding throughout the Northern Hemisphere. Great Britain is now grinding its way through frequent snows and a prolonged freeze that’s tangled transportation and brought supplies of heating oil and road treatments to worrisome lows. Temperatures below 20°F (–6.7°C) could dive as far south as Spain this weekend, with more snow on tap for London.